The present invention relates to alarm buzzers and especially to alarm buzzers for use with fire alarms, burglar alarms, and the like.
In the past, it has been conventional to make inexpensive alarms, such as electrical buzzers, for use in a wide variety of products, including smoke alarms, fire alarms, burglar alarms, and typically, these alarms are operated by small batteries, such as a nine (9) volt battery, which operates an oscillator or vibrator which drives a transducer. In one typical prior art alarm buzzer, a piezoelectric transducer is utilized mounted in a casing and driven by an oscillator to produce an alarm when actuated. Alarm buzzers of this type have generally been able to produce a sound pressure level of approximately eighty (80) decibels when measured at ten (10) feet in front of the alarm buzzer. The level of response can be increased by using a larger voltage in a larger battery, but in most alarm actuated devices, it is desirable to have a compact alarm buzzer operated by a small battery or pack of batteries. Prior art alarm buzzers have operated satisfactorily, but it has been felt that a higher sound pressure level is desirable. The present invention is directed towards increasing the efficiency of a buzzer alarm to improve the sound pressure level, utilizing the same voltage source and transducer, thereby allowing the unit to fit into conventional alarm systems without greatly increasing the cost of the buzzers and of the alarms.